Background: Over-assisted mechanical ventilation(MV) is associated with respiratory muscle disuse atrophy. Meanwhile, under-assisted MV causes P-SILI or respiratory muscle injuries. And both cause poor outcomes. Aims: To prove the association between the degree of respiratory effort measured by P0.1, predicted Pmus and predicted Δtranspulmonary pressure(ΔPL) with ventilator-free days and mortality at 28 days. Methods: We conducted a prospective observational study in respiratory failure patients who required invasive MV. Results: 80 patients with respiratory failure were included and categorized into 3 groups regarding P0.1 and predicted Pmus, 2 groups regarding the predicted ΔPL. The ventilator-free days at 28 days(28-VFDs) were significantly longer in the P0.1 group between 1.5-3.5 cmH2O than the group those < 1.5 and > 3.5 cmH2O (24 [19-25], 15 [0-24]and 14 [0-26] days respectively, P=0.008). Likewise, the predicted Pmus group between 5-10 cmH2O showed significantly longer ventilator-free days than those of predicted Pmus < 5 and > 10 cmH2O (24 [14-26] , 13 [0-23] and 23 [8-25] days respectively, P=0.045). The predicted ΔPL ≤ 20 cmH2O group had significantly longer ventilator-free days than those of predicted ΔPL > 20 cmH2O (24 [15-26] vs. 17 [0-24] days, P=0.007). The association with significantly lower 28-day mortality was found in groups of P0.1 between 1.5-3.5 cmH2O(P=0.039) and predicted ΔPL ≤ 20 cmH2O (P=0.022). Conclusions: The degree of respiratory effort measured by P0.1, predicted Pmus and ΔPL was associated with 28-VFDs. In addition,the P0.1 and predicted ΔPL were associated with 28-day mortality.
During mechanical ventilation, minimizing respiratory drive and effort becomes routine to prevent patient-ventilator asynchrony (PVA). As we know, PAV associates with poor outcomes in ICU patients. As a result, prescribing sedative drugs in combination with neuro-muscular blocking agents commonly appears in many ICUs. However, many patients develop adverse events from unloading respiratory muscles, resulting in prolonged mechanical ventilator and bad clinical outcomes. This review describes both sides of the adverse effect of respiratory drive and effort and tries to suggest the optimum point, believing that it may be associated with better outcomes.
Several parameters are used to predict successful extubation but their accuracy varies among studies. We hypothesized that combining conventional and diaphragmatic parameters would be more effective than using just one. Our primary objective was to evaluate the performance of the respiratory rate in relation to the diaphragm thickening fraction (RR/DTF) ratio to predict the success of extubation.We enrolled 130 adult patients who required invasive mechanical ventilation, planned to be extubated, and used a spontaneous breathing trial (SBT) in the intensive care unit from July 2020 to April 2022. We measured the conventional parameters and the diaphragmatic parameters 2 h after SBT. The RR/DTF was calculated by dividing the respiratory rate (RR) by the diaphragm thickening fraction (DTF). The definition of weaning success is successful extubation within 48 h.Of 130 patients, 8 patients (6.2%) were reintubated within 48 h. The RR/DTF was significantly lower in the successful extubation group than in the extubation failure group (right hemidiaphragm; 0.47 (0.33-0.64) vs 1.1 (0.6-2.32), p < 0.001 and left hemidiaphragm; 0.45 (0.31-0.65) vs 0.78 (0.48-1.75), p < 0.001). The right RR/DTF using a cut-off point at ≤ 0.81 had a sensitivity of 87.7%, a specificity of 75%, and areas under the receiver operating characteristic curve (AUROC) of 0.762 for predicting successful extubation (p = 0.013). The sensitivity, specificity, and AUROC for predicting extubation success of right DTF at a cut-off point of ≥ 26.2% were 84.3%, 62.5%, and 0.775, respectively (p = 0.009).The RR/DTF ratio is a promising tool for predicting extubation outcome. Additionally, using RR/DTF was more reliable than conventional or diaphragmatic parameters alone in predicting extubation success.
Abstract Background Tidal expiratory flow limitation (EFL T ) complicates the delivery of mechanical ventilation but is only diagnosed by performing specific manoeuvres. Instantaneous analysis of expiratory resistance (Rex) can be an alternative way to detect EFL T without changing ventilatory settings. This study aimed to determine the agreement of EFL T detection by Rex analysis and the PEEP reduction manoeuvre using contingency table and agreement coefficient. The patterns of Rex were explored. Methods Medical patients ≥ 15-year-old receiving mechanical ventilation underwent a PEEP reduction manoeuvre from 5 cmH 2 O to zero for EFL T detection. Waveforms were recorded and analyzed off-line. The instantaneous Rex was calculated and was plotted against the volume axis, overlapped by the flow-volume loop for inspection. Lung mechanics, characteristics of the patients, and clinical outcomes were collected. The result of the Rex method was validated using a separate independent dataset. Results 339 patients initially enrolled and underwent a PEEP reduction. The prevalence of EFL T was 16.5%. EFL T patients had higher adjusted hospital mortality than non-EFL T cases. The Rex method showed 20% prevalence of EFL T and the result was 90.3% in agreement with PEEP reduction manoeuvre. In the validation dataset, the Rex method had resulted in 91.4% agreement. Three patterns of Rex were identified: no EFL T , early EFL T , associated with airway disease, and late EFL T , associated with non-airway diseases, including obesity. In early EFL T , external PEEP was less likely to eliminate EFL T . Conclusions The Rex method shows an excellent agreement with the PEEP reduction manoeuvre and allows real-time detection of EFL T . Two subtypes of EFL T are identified by Rex analysis. Trial registration : Clinical trial registered with www.thaiclinicaltrials.org (TCTR20190318003). The registration date was on 18 March 2019, and the first subject enrollment was performed on 26 March 2019.
Peak expiratory flow rate (PEFR) is the best assessment of asthma severity during acute asthmatic attack (AAA). Since PEFR represents an effort-dependent flow from large airways, we wonder if the falls of PEFRs during AAA result from expiratory tracheobronchial collapses (TBC). This study aims to explore the existence of TBC during AAA and, if any, its influence on PEFR.
Methods: We conducted a cross sectional cohort in patients with AAA treated at the emergency department (ED). Along with the continued monitoring of PEFRs, TBC assessments by low dose high resolution computerized tomogram (HRCT) were performed twice for each patient, i.e. at ED (T1) and at 6th-8th week (T2) (PEFR variability <15%). TBCs in both periods were quantified and changes were compared with changes in the corresponding PEFRs.
Results: Of the 34 enrolled patients, 5 were excluded due to failures in forced expiratory maneuvers. At T1, all of the 29 patients exhibited variable degree of TBCs (% inspiration) (mean 44.05±19.79). 2nd HRCTs were not done in 5 patients for repeated exacerbations. Of the 24 patients who completed 2 HRCTs, 72.91% of them showed improvement of TBCs over time. Comparisons of the improvements of TBCs with those of PEFRs (% predicted) between T1 and T2 showed that TBC changes at the level of trachea near to the carina (L3) correlated well with PEFR changes (p<0.05, r=0.7). At T1, the magnitudes of TBCs at L3 also correlated with the corresponding PEFRs (p<0.05, r=0.5).
Conclusions: Patients with AAA demonstrated presences of TBCs of different severities which mostly improved with time. TBC at tracheal rings near to the carina was most prominent that influenced the changes of PEFRs. TBCs thus play roles in the falls of PEFRs during AAA.
Despite the extensive use of continuous positive airway pressure (CPAP) in various respiratory failure conditions, its role in acute asthmatic attack is uncertain [1-3]. This study aims at exploring the efficacy of CPAP when use in addition to the conventional treatment of acute asthma exacerbation in the emergency department (ED).
This chapter contains sections titled: Introduction Back to basics Effects of transfusion on cellular oxygenation The effects of transfusions on oxygen extraction The microcirculatory effects of blood transfusions Conclusion References
Background: Clinical heterogeneity was observed among COVID-19 patients with acute respiratory distress syndrome (CARDS). The heterogeneity of disease was contributed to different clinical progression, responses to treatment, and mortality. Objective: We aim to study the phenotype and associated mortality of COVID-19 respiratory failure in Thai patients. Methods: We conducted a single-center, retrospective observational study. The data were collected in CARDS who received an invasive mechanical ventilator in ICU. Patient-related data were collected at admission before the onset of respiratory failure. The main features include demographics data, SOFA score, laboratory, CXR severity score, treatment during hospitalization, and the following data at the onset of respiratory failure during invasive mechanical ventilator. We also collected patients’ status at 28-day, in-hospital complications, and ventilator-free days at 28-day after intubation. The latent profile analysis was performed to identify distinct phenotypes. After identifying phenotypes, characteristics and clinical outcomes were compared between phenotypes. The primary outcome was the phenotype and associated mortality of COVID-19 respiratory. Secondary outcomes include characteristics of phenotype, ventilator-free days, response to treatment, and complications in each phenotype. Discussion: This study aims to identify the phenotype of COVID-19SARS-CoV-2 Respiratory Failure in Thai Patients The different phenotypes may be associated with varying responses to treatment and outcomes that the result of this study may be useful for determining treatment and predicted prognosis of COVID-19 SARS-CoV-2 Respiratory Failure In Thai Patients. Ethics and dissemination: The study protocol was approved by the Institution Review Board of Ramathibodi Hospital, Mahidol University, Thailand (No. MURA2021/740). We plan to disseminate the results in peer-reviewed critical care medicine or pulmonology related journal, conferences nationally and internationally.
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